/*****************************************************************************
 * Open MCT Web, Copyright (c) 2014-2015, United States Government
 * as represented by the Administrator of the National Aeronautics and Space
 * Administration. All rights reserved.
 *
 * Open MCT Web is licensed under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * http://www.apache.org/licenses/LICENSE-2.0.
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 * Open MCT Web includes source code licensed under additional open source
 * licenses. See the Open Source Licenses file (LICENSES.md) included with
 * this source code distribution or the Licensing information page available
 * at runtime from the About dialog for additional information.
 *****************************************************************************/

define([
    'moment'
], function (
    moment
) {

    var DATE_FORMAT = "YYYY-MM-DD h:mm:ss.SSS a",
        DATE_FORMATS = [
            DATE_FORMAT,
            "YYYY-MM-DD h:mm:ss a",
            "YYYY-MM-DD h:mm a",
            "YYYY-MM-DD"
        ];

    /**
     * @typedef Scale
     * @property {number} min the minimum scale value, in ms
     * @property {number} max the maximum scale value, in ms
     */

    /**
     * Formatter for UTC timestamps. Interprets numeric values as
     * milliseconds since the start of 1970.
     *
     * @implements {Format}
     * @constructor
     * @memberof platform/commonUI/formats
     */
    function LocalTimeFormat() {
    }

    /**
     * Returns an appropriate time format based on the provided value and
     * the threshold required.
     * @private
     */
    function getScaledFormat (d) {
        var m = moment.utc(d);
        /**
         * Uses logic from d3 Time-Scales, v3 of the API. See
         * https://github.com/d3/d3-3.x-api-reference/blob/master/Time-Scales.md
         *
         * Licensed
         */
        return [
            [".SSS", function(m) { return m.milliseconds(); }],
            [":ss", function(m) { return m.seconds(); }],
            ["hh:mma", function(m) { return m.minutes(); }],
            ["hha", function(m) { return m.hours(); }],
            ["ddd DD", function(m) {
                return m.days() &&
                    m.date() != 1;
            }],
            ["MMM DD", function(m) { return m.date() != 1; }],
            ["MMMM", function(m) {
                return m.month();
            }],
            ["YYYY", function() { return true; }]
        ].filter(function (row){
            return row[1](m);
        })[0][0];
    };

    /**
     *
     * @param value
     * @param {Scale} [scale] Optionally provides context to the
     * format request, allowing for scale-appropriate formatting.
     * @returns {string} the formatted date
     */
    LocalTimeFormat.prototype.format = function (value, scale) {
        if (scale !== undefined){
            var scaledFormat = getScaledFormat(value, scale);
            if (scaledFormat) {
                return moment.utc(value).format(scaledFormat);
            }
        }
        return moment(value).format(DATE_FORMAT);
    };

    LocalTimeFormat.prototype.parse = function (text) {
        return moment(text, DATE_FORMATS).valueOf();
    };

    LocalTimeFormat.prototype.validate = function (text) {
        return moment(text, DATE_FORMATS).isValid();
    };

    return LocalTimeFormat;
});